> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/s/safe_and_sophie_germain_primes.md).

# Safe and Sophie Germain primes

```ruby
^Inf -> lazy.grep{|p| all_prime(p, 2*p + 1) }.first(50).slices(10).each{
    .join(', ').say
}
```

#### Output:

```
2, 3, 5, 11, 23, 29, 41, 53, 83, 89
113, 131, 173, 179, 191, 233, 239, 251, 281, 293
359, 419, 431, 443, 491, 509, 593, 641, 653, 659
683, 719, 743, 761, 809, 911, 953, 1013, 1019, 1031
1049, 1103, 1223, 1229, 1289, 1409, 1439, 1451, 1481, 1499
```